多线程与高并发(咕泡)

在java中如何使用多线程

1.实现Runnable接口创建线程

public class RunnableThreadExample implements Runnable{
    @Override
    public void run() {
        System.out.println("RunnableThreadExample.run");
    }

    public static void main(String[] args) {
        Thread thread = new Thread(new RunnableThreadExample());
        thread.start();
    }
}

2.继承Thread类创建线程

public class ThreadExample extends Thread{

    @Override
    public void run() {
        System.out.println("ThreadExample.run");
    }

    public static void main(String[] args) {
        ThreadExample threadExample = new ThreadExample();
        threadExample.start();
    }
}

3.实现Callable接口并创建带返回值的线程

public class CallableExample implements Callable<String> {

    @Override
    public String call() throws Exception {
        return "执行结果:SUCCESSS";
    }

    public static void main(String[] args) throws ExecutionException, InterruptedException {
        CallableExample callableExample = new CallableExample();
        FutureTask<String> futureTask = new FutureTask<>(callableExample);
        Thread thread = new Thread(futureTask);
        thread.start();
        System.out.println(futureTask.get());
    }
}

多线程的基本原理

线程的运行状态

1.NEW-----新建状态--------new Thread()时的状态
2.RUNNABLE------运行状态---------start()方法启动线程后的状态
3.BLOCKED------阻塞状态-------执行synchronized代码并且未抢占到同步锁时的状态
4.WAITING-----等待状态------调用Object.wait()等方法的状态
5.TIMED_WAITING-----超时等待状态------调用sleep(timeout)时的状态，超时后会自动唤醒
6.TERMINATED----终止状态-----run()方法的指令执行完成后的状态